Ya, that frame is a gasbike cheap knock-off of the real Grubee Skyhawk frames, for example no rear disc mount.
I want to put a 4 stroke on thats over 50cc because I live in a very hilly area. I'm looking at the predator 79cc kit right now,
but im still wondering if theres a better option out there.
Any input or suggestions would be much appreciated.
Yes, there is a pretty good 'other option' now, well soon as I have a heath issue right now.
The 49cc or 53cc are enough to power you up to ~40mph and tackle hills and still maintain ~20mph because of the bike gears.
I modify a Skyhawk 4G to a 10G long shaft of my design to drop the engine output over the pedal systems sprockets.
The main 100T belt pulley is a freewheel, which means you have virtually no drag from the engine part even with the engine off when you pedal.
In short gears rock ;}